Spinning chimney

ABSTRACT

A SPINNING CHIMNEY TO BE USED FOR THE QUENCHING OF MOLTEN POLYMERIC FILAMENTS, SAID CHIMNEY HAVING SIDES AND A BACK WITH THE SIDE COMPRISING CONVERGING WALLS WHICH CONFORM TO THE PATH OF FILAMENTS FROM THE SPINNERET TO THE CONVERGENCE GUIDE AND DIVERGING WINGS WHICH COMMUNICATE WITH THE LEADING EDGES OF THE WALLS, AND A PLENUM   CHAMBER ASSOCIATED WITH THE UPPER PORTION OF THE BACK OF THE CHIMNEY FOR DIRECTING THE FLOW OF AIR OVER THE FILAMENTS.

Jan. 5, 1971 A, E. LEYBOURNE Ill, ETAL SPINNING CHIMNEY Filed NOV. 15,1968 FIG. I.

INVENTORS A. E; LEYBOURNEE J. R. DEES ATTORNEY United States Patent O3,551,949 SPINNING CHIMNEY Allen E. Leybourne III, and John R. Dees,Decatur, Ala.,

assignors to Monsanto Company, St. Louis, M0., a

corporation of Delaware Filed Nov. 15, 1968, Ser. No. 776,032 Int. Cl.D01d 5/04 U.S. Cl. 18-8 7 Claims ABSTRACT OF THE DISCLOSURE A spinningchimney to be used for the quenching of molten polymeric filaments, saidchimney having sides and a back with the sides comprising convergingwalls which conform to the path of filaments from the spinneret to theconvergence guide and diverging wings which communicate with the leadingedges of the walls, and a plenum chamber associated with the upperportion of the back of the chimney for directing the flow of air overthe filaments.

BACKGROUND OF THE INVENTION (1) Field of the invention This inventionrelates to the production of synthetic filaments, yarns, ribbons and thelike from fiber-forming polymers. More specifically, this inventiondeals with improvements in the apparatus employed in cooling the moltenstructures extruded from a spinneret.

(2) Description of the prior art In practice, melt-spun filaments areextruded from a spinneret and enter a spinning chimney or quenchingchamber where they are subjected to a cross-current flow of a quenchingmedium.

Heretofore, a number of different spinning chimneys have been known andall have suffered from various insufiiciencies; being inadequate on thewhole. Some have suffered because of the uneconomical volume of air orquenching medium required to attain the desired result. Others havesuffered in that much of the air used is wasted; never reaching thefilaments. Still others have suffered in that they are cumbersome whileyet others are structurally uneconomical and/ or unsuitable.

One of the most important disadvantages of some of the prior artspinning chimneys is the quality of filaments produced therewith; beingpoorer on the whole.

SUMMARY OF THE INVENTION Accordingly, the above disadvantages areovercome and the quenching of molten polymeric filaments is accomplishedthrough the use of a spinning chimney having a back and sides with saidsides comprising 1) converging walls which conform to the path offilaments from the spinneret to the convergence guide, and (2) divergingwings which communicate with the leading edges of the Walls. Thequenching fluid is directed into the chimney and over the filamentsthrough the back of the chimney which is foraminous over a part of itsupper half.

Therefore, an object of this invention is the overall improvement ofsuch properties as the denier uniformity, tenacity and dyeability of thespun filaments.

Another object of the invention is to provide a spinning chimney inwhich there is a more efficient use of the quenching medium.

These and other objects and advantages will become more readily apparentwhen considered in conjunction with the remainder of the specificationand accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of aspinning chimney made in accordance with the teachings of this inventionand shown in association with a spin pack, a convergence guide, and aplenum chamber.

FIG. 2 is a vertical sectional view taken substantially along lines 2-2of FIG. 1 showing the spinning chimney, plenum chamber, convergenceguide, and spin pack.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment asshown in FIG. 1 and FIG. 2 includes generally a plenum chamber 16, aspin pack 14 including a spinneret, a face plate 13 which is used toprotect the spinneret face, a convergent spinning chimney generallydenoted by reference numeral 1, and a convergence guide 15. The plenumchamber 16 has imperforate top, bottom, and side walls, as well as afront distribution plate 12 which is suitably perforated. Spinningchimney 1 has sides made up of walls 2, through which a plurality offilaments 17 travel directly from spin pack 14 to convergence guide 15.In the embodiment shown, walls 2 extend perpendicularly from back 11 fora distance with the terminus thereof forming leading edges 4 whichcommunicate at an angle with divergent wings 7 which can be integraltherewith.

As shown, walls 2 are substantially trapezoidal in shape with theparallel sides being the tops and bottoms thereof. Wings 7 aresubstantially right-triangular in shape With the hypotenuses thereofcommunicating with the leading edges 4 of walls 2 which are secured inplace by any suitable means. The upper portion, or a major part of theupper half, of the back of chimney 1 is occupied by distribution plate12 and the lower portion of the back is either open or occupied by plate11.

Depending upon the length of the chimney to be used, a greater area ofthe back of the chimney may be required in order to attain the desiredflow and distribution of the quenching medium. In other words, forshorter chimneys, a major portion of the back can be foraminous, or opento accommodate a distribution plate.

It would also be possible to integrate distribution plate 12 into thechimney structure and adapt it for attachment to the remainder of theplenum chamber in covering relationship to an appropriate aperture. Ineither event, a quenching medium, usually air, flows under pressurethrough the foraminous plate 12 into chimney 1 for cross-current flowthrough filaments 17.

While the walls and wings are preferably planar and meet at an anglebeing less than this is not to say that they may not be arcuate; meetingat an angle of more or less than 180. If the arcuate wings and walls metat 180, a continuous arcuate surface would be formed.

As is apparent from FIG. 1, the trapezoidal-shaped walls 2 convergetoward the bottom of chimney 1 in such a manner as to conform to theflow of filaments 17 from spin pack 14 to convergence guide 15; walls 2being closely adjacent to the paths of travel of the outer mostfilaments.

Usually, the illustrated apparatus is physically located above itsassociated windup area and the filaments 17 pass downwardly thereto. Insome prior art instances, when the apparatus is placed in operation, abundle of filaments is forced downwardly through a transfer tube to thewindup area by compressed air. Once the individual filaments and thebundle as a whole are running properly through the tube, they areseparated and located on a convergence guide. Another possibility is toapply a vacuum to the bottom of the transfer tube and draw the filamentsout through a flexible hose suitably connected to a fan and filtersystem. The hose can be used to draw off the filaments to awaste-collecting system while the individual filaments are beingstrung-up.

It is easily appreciated that the structure of the instant chimneyallows for an operator to manually throw the filaments through thebottom of the chimney for stringing-up in the windup area below, thuseliminating expensive tubes and vacuum devices. The structure of thechimney is such that the filaments are funneled or guided through thebottom when thrown.

In normal operation, the quenching medium flows cross-current throughthe filaments 17 at sufficient velocity as in a conventional rectangularchimney. However, there is a more efiicient use of the medium since thereduction in the cross-sectional area of the flow path through thechimney permits a reduction in total air flow while maintaining the sameflow velocity.

Uniformity of air flow velocity transverse to the chimney, as shown bythe arrows in FIG. 2, is dramatically improved giving rise tospectacular improvements in the physical properties of the filamentsspun in addition to a substantial reduction in quenching mediumrequirements.

Tests were conducted during the spinning of polyester fiber(polyethylene terephthalate) wherein the polymer throughput was 88p.p.h. (pounds per hour). When a rectangular chimney was used having anair flow of 1000 c.f.m. (cubic feet per minute) at 20 C., filaments wereproduced having a denier coeflicient of variation of 20 percent asdetermined from photomicrographs of fiber cross-sections. Fibers spunthrough the chimney of this invention with an air flow of 500 c.f.m. hada denier coefficient of variation of 14 percent. At an air flow of 50c.f.rn. through a rectangular chimney, only very marginal quenching waseffected as evidenced by unquenched filaments which periodically brokeand blew out of the chimney, whereas with the chimney of this inventionspinning was continuous and satisfactory, and the marginal rate was 350c.f.m. at 20 C.

As shown by the arrows in FIG. 2, the quenching medium flaws into thechimney through foraminous plate 12, and exits through the front of thechimney and between wings 7. With a trapezoidally-shaped chimney, freespace for extraneous wasteful air current in the front portion of thechimney is minimized thus forcing a major portion of the medium to fiowcross-current to the filament bundle. In a rectangular chimney, there isa relatively large amount of wasteful space available for extraneousflow around the sides of the bundle. Smoke pattern tests have shown thefiow in these side areas of a rectangular chimney to be productive of aconsiderable amount of turbulence. Reduction of this turbulence isbelieved to be in part responsible for the improved quality of filamentsspun through a trapezoidal chimney.

It is believed that the wings function to keep any stray air currentswhich exist within the room from affecting the bundle of filaments asthey pass through the chimney. Convection and other currents couldpossibly change or hinder the uniform flow of filaments.

Another theory which may explain the successful operation of the chimneyof this invention is that turbulence is present with air or fluidflowing past any edge and by having wings on the leading edges of thewalls, an edge which would create noticeable turbulence would bedisplaced further from the bundle of filaments.

A definite advantage, though not affecting the quality of the filamentsor operation of the chimney, is that there is less likelihood of theoperator sustaining injury when the yarn or bundle is thrown through thebottom to the windup area below.

Although specific reference has been made to the use of the polyester,it is apparent that the improvements disclosed herein are equallyapplicable to the melt-spinning of any organic fiber-formingcomposition. In this and other respects, it is accordingly intended thatthe present invention should be limited only by the scope of theappended claims.

We claim:

1. A spinning chimney characterized in having a back and sides, saidsides comprising walls which converge from top to bottom, and whichextend from the back of the chimney for a distance, the terminus thereofforming leading edges which communicate at an angle with divergingwings.

2. A spinning chimney according to claim 1 wherein the wings are planar.

3. A spinning chimney according to claim 1 wherein the walls are planar.

4. A spinning chimney according to claim 1 wherein the walls extendperpendicularly from the back of the chimney.

5. A spinning chimney according to claim 1 wherein the walls aresubstantially trapezoidal in shape with the tops and bottoms thereofforming the parallel sides.

6. A spinning chimney according to claim 1 wherein the wings aresubstantially right-triangular in shape with the hypotenuses thereofconforming to the leading edges of the walls.

7. A spinning chimney according to claim 1 wherein the back of thechimney is foraminous over part of its upper half.

References Cited UNITED STATES PATENTS 3,067,459 12/1962 Brand.3,108,322 10/1963 Tate. 3,169,271 2/ 1965 Musser. 3,335,210 8/1967Vinicki.

ANDREW R. JUHASZ, Primary Examiner L. GILDEN, Assistant Examiner US. Cl.X.R. 264-176

